Allow single push to either port 1 or 2

Author: polybeandip

pifo-design/src/flow_scheduler.sv

@@ -103,23 +103,26 @@ module FlowScheduler #(parameter SIZE = 10, parameter FLOWS = 10) (
             for ( int i = 0; i < SIZE; i++ ) valids[i] <= 0;
         end
         else begin
-            // swap if push_2's rank < push_1's rank
+            // swap if 
+            // 1) both pushes are valid and push_2's rank < push_1's rank
+            // 2) push_2 is valid but push_1 isn't
             for ( int i = 0; i < 2; i++ ) begin
-                if ( push_valid_C[1] && push_rank_C[1] <  push_rank_C[0] ) begin
+                if ( push_valid_C[1] && ((push_rank_C[1] < push_rank_C[0]) || !push_valid_C[0]) ) begin
                     insert_idx_S[i] <= insert_idx_C[1 - i];
                     push_value_S[i] <= push_value_C[1 - i];
                     push_rank_S[i]  <= push_rank_C[1 - i];
                     push_flow_S[i]  <= push_flow_C[1 - i];
+                    push_valid_S[i] <= push_valid_C[1 - i];
                 end
                 else begin
                     insert_idx_S[i] <= insert_idx_C[i];
                     push_value_S[i] <= push_value_C[i];
                     push_rank_S[i]  <= push_rank_C[i];
                     push_flow_S[i]  <= push_flow_C[i];
+                    push_valid_S[i] <= push_valid_C[i];
                 end
             end
 
-            push_valid_S <= push_valid_C;
             pop_valid_S  <= pop_valid_C;
 
             if ( push_valid_C[0] && push_valid_C[1] ) 

pifo-design/tb/tb_flow_scheduler.cpp

@@ -11,7 +11,13 @@
 #define SIZE       10
 #define WAVEFORM   "flow_scheduler.vcd"
 
-enum class Op { Push, Pop, PushPush, Nop };
+enum class Op { 
+    Push1,    // single push through push port 1
+    Push2,    // single push through push port 2
+    Pop, 
+    PushPush, // dual push through both ports
+    Nop 
+};
 
 struct FlowValue {
     unsigned int flow;
@@ -48,21 +54,25 @@ std::vector<Cmd> generate_commands(int num_cmds) {
 
     for (int i = 0; i < num_cmds; i++) {
         Cmd cmd;
-        if (!size || size == SIZE) // to avoid over/underflow
-            cmd.op = !size ? Op::Push : Op::Pop;
+        if (size == SIZE) // to avoid overflow
+            cmd.op = Op::Pop;
+        else if (!size)   // to avoid underflow
+            cmd.op = rand() % 2 ? Op::Push1 : Op::Push2;
         else {
-            int rng = rand() % 4;
-            switch (rng) {
+            switch (rand() % 5) {
                 case 0:
-                    cmd.op = Op::Push;
+                    cmd.op = Op::Push1;
                     break;
                 case 1:
-                    cmd.op = Op::Pop;
+                    cmd.op = Op::Push2;
                     break;
                 case 2:
-                    cmd.op = size == SIZE - 1 ? Op::Push : Op::PushPush;
+                    cmd.op = Op::Pop;
                     break;
                 case 3:
+                    cmd.op = size == SIZE - 1 ? Op::Push1 : Op::PushPush;
+                    break;
+                case 4:
                     cmd.op = Op::Nop;
                     break;
             }
@@ -79,7 +89,8 @@ std::vector<Cmd> generate_commands(int num_cmds) {
 
         int delta;
         switch (cmd.op) {
-            case Op::Push:     delta = 1;  break;
+            case Op::Push1:    
+            case Op::Push2:    delta = 1;  break;
             case Op::Pop:      delta = -1; break;
             case Op::PushPush: delta = 2;  break;
             case Op::Nop:      delta = 0;  break;
@@ -103,10 +114,14 @@ std::vector<FlowValue> compute_expected(std::vector<Cmd> cmds) {
 
     for (Cmd cmd : cmds) {
         switch (cmd.op) {
-            case Op::Push:
+            case Op::Push1:
                 pifo.push(cmd.data_1);
                 break;
 
+            case Op::Push2:
+                pifo.push(cmd.data_2);
+                break;
+
             case Op::Pop:
                 out.push_back(pifo.top().flow_value);
                 pifo.pop();
@@ -167,8 +182,8 @@ std::vector<FlowValue> simulate(std::vector<Cmd> cmds, const char* waveform) {
             else {
                 Cmd cmd = *it;
 
-                dut->push_1 = cmd.op == Op::Push || cmd.op == Op::PushPush;
-                dut->push_2 = cmd.op == Op::PushPush;
+                dut->push_1 = cmd.op == Op::Push1 || cmd.op == Op::PushPush;
+                dut->push_2 = cmd.op == Op::Push2 || cmd.op == Op::PushPush;
                 dut->pop    = cmd.op == Op::Pop;
 
                 dut->push_rank_1  = cmd.data_1.rank;
@@ -224,8 +239,12 @@ int main(int argc, char** argv, char** env) {
                          r_2 = c.data_2.rank, 
                          f_2 = c.data_2.flow_value.flow;
             switch (c.op) {
-                case Op::Push:
-                    printf("push(v=%u, f=%u, r=%u)\n", v_1, f_1, r_1);
+                case Op::Push1:
+                    printf("push(v=%u, f=%u, r=%u) (port 1)\n", v_1, f_1, r_1);
+                    break;
+
+                case Op::Push2:
+                    printf("push(v=%u, f=%u, r=%u) (port 2)\n", v_2, f_2, r_2);
                     break;
 
                 case Op::Pop:

pifo-design/tb/tb_rank_store.cpp

@@ -53,8 +53,7 @@ std::vector<Cmd> generate_commands(int num_cmds) {
             cmd.op = Op::Push;
         }
         else {
-            int rng = rand() % 4;
-            switch (rng) {
+            switch (rand() % 4) {
                 case 0: cmd.op = Op::Push;    break;
                 case 1: cmd.op = Op::Pop;     break;
                 case 2: